Paleofantasy: What Evolution Really Tells Us About Sex, Diet, and How We Live

by Marlene Zuk

Norton

Marlene Zuk is an evolutionary biologist at the University of Minnesota and Paleofantasy targets the movement that insists we are biologically adapted to a Palaeolithic diet and lifestyle.

On the face of it, the idea seems plausible: in the standard model of human evolution, anatomically modern Homo sapiens have been around for about 200,000 years, only 10,000 of them as farmers, let alone modern industrial people. Evolution is slow, so it stands to reason that we haven't had time to adapt to the huge changes in our lifestyle.

However, many evolutionary biologists, including Zuk, believe that this is wrong. The changes wrought in the human genome by settled farming and the consequent enormous growth in population can indeed be seen: they are profound and have been rapid.

"Drinka Pinta Milka Day" could be the slogan for the new thinking. All mammalian babies can digest milk, but the gene that allows this switches off at the age of weaning - except in many modern humans. In the most northern human populations, i.e. Scandinavian, almost 100 per cent can digest milk.

The percentage declines as you track southeast. A single base pair mutation allows adults to drink milk. It emerged around 7,500 years ago with the first dairying in southern Turkey, and as these herders moved north and west the milk drinkers out-bred the rest. This is rapid evolution and it's not the only case.

Zuk discusses the evidence that humans are still evolving. On one level, trying to eat like a caveman is simply the latest version of Rousseau's noble savage. On another, it's just one more crazy consumer society cult, with its faux-sophisticated peddling of pseudo-knowledge. Zuk quotes a typical example: "there's three problems with tubers: a) Poisonous substances; b) Carb load; c) Problems we are yet to discover."

This is about the potato: a significant world problem of our time, no doubt.

Zuk spends too much time swatting these know-nothings, but her take on the many controversies and uncertainties surrounding evolution is both wise and measured. Zuk is especially good at explaining how evolution is a tinkerer, an opportunist; it isn't going anywhere and it never gets there. The idea, so often quoted, that some species are "perfectly adapted to their environment" is wrong. Both the environment and the genes are always drifting to some place else and there is no diet that would be "evolutionarily correct".